Scale the OSR optimization threshold by loop nesting depth.

runtime/vm/flow_graph_builder.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_FLOW_GRAPH_BUILDER_H_
 #define VM_FLOW_GRAPH_BUILDER_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 102 matching lines @@
   const Array& ic_data_array() const { return ic_data_array_; }
 
   void Bailout(const char* reason);
 
   intptr_t AllocateBlockId() { return ++last_used_block_id_; }
   void SetInitialBlockId(intptr_t id) { last_used_block_id_ = id; }
 
   void set_context_level(intptr_t value) { context_level_ = value; }
   intptr_t context_level() const { return context_level_; }
 
+  void IncrementLoopDepth() { ++loop_depth_; }
+  void DecrementLoopDepth() { --loop_depth_; }
+  intptr_t loop_depth() const { return loop_depth_; }
+
   // Each try in this function gets its own try index.
   intptr_t AllocateTryIndex() { return ++last_used_try_index_; }
 
   // Manage the currently active try index.
   void set_try_index(intptr_t value) { try_index_ = value; }
   intptr_t try_index() const { return try_index_; }
 
   void AddCatchEntry(CatchBlockEntryInstr* entry);
 
   intptr_t num_copied_params() const {
@@ skipping 29 matching lines @@
 
   const intptr_t num_copied_params_;
   const intptr_t num_non_copied_params_;
   const intptr_t num_stack_locals_;  // Does not include any parameters.
   InlineExitCollector* const exit_collector_;
 
   intptr_t last_used_block_id_;
   intptr_t context_level_;
   intptr_t last_used_try_index_;
   intptr_t try_index_;
+  intptr_t loop_depth_;
   GraphEntryInstr* graph_entry_;
 
   // Outgoing argument stack height.
   intptr_t args_pushed_;
 
   // The deopt id of the OSR entry or Isolate::kNoDeoptId if not compiling
   // for OSR.
   const intptr_t osr_id_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(FlowGraphBuilder);
@@ skipping 330 matching lines @@
   // Output parameters.
   GrowableArray<TargetEntryInstr**> true_successor_addresses_;
   GrowableArray<TargetEntryInstr**> false_successor_addresses_;
 
   intptr_t condition_token_pos_;
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_BUILDER_H_